Jet ignition device for a pyrotechnic fuze

ABSTRACT

An ignition device having an open-ended case with a primer closing one end and a nozzle closing the opposite end. An orifice is provided in the nozzle and the orifice is closed by a frangible disk attached to the outer end of said nozzle. An ignition pellet is contained in said case adjacent said nozzle and detonation of said primer ruptures said frangible disk and ignites said ignition pellet.

United States Patent 1191 Clifton et al.

JET IGNITION DEVICE FOR A PYROTECHNIC FUZE Inventors: John R. Clifton; Gary S. Edwards,

both of Bedford, Ind.

The United States of America as represented by the Secretary of the Navy, Washington, DC.

Filed: Jan. 5, 1973 Appl. No.: 321,435

Assignee:

US. Cl. 102/70 R, 102/49.7 Int. Cl. F42c 19/08 Field of Search 102/49.7, 70, 70.2, 86.5;

References Cited UNITED STATES PATENTS 8/1949 Carr 60/256 Primary Examiner-Verlin R. Pendegrass Attorney, Agent, or Firm-R. S. Sciascia; Paul S.

Collignon [5 7] ABSTRACT An ignition device having an open-ended case with a primer closing one end and a nozzle closing the opposite end. An orifice is provided in the nozzle and the orifice is closed by a frangible disk attached to the outer end of said nozzle. An ignition pellet is contained in said case adjacent said nozzle and detonation of said primer ruptures said frangible disk and ignites said ignition pellet.

1 Claim, 2. Drawing Figures JET IGNITION DEVICE FOR A PYROTECI'INIC FUZE CROSS-REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION The present invention relates to a jet ignition system and more particularly to an ignition system for a pyrotechnic item, such as an aircraft parachute flare.

In the above-referenced patent application, there is shown a device for igniting a delay fuze in an aircraft parachute flare. A primer is positioned in one end of a holder and an ejection plunger is positioned in the opposite end. The ejection plunger contains a quantity of black powder and has a pointed forward end and has a passageway so that heat and flame from a burning of the black powder can pass into the forward end and exit'through a plurality of holes in the pointed end. Detonation of the primer drives the ejection plunger into a delay fuze and simultaneously ignites a fixed delay which subsequently ignites the black powder.

The device shown and described in the abovereferenced patent application has several disadvantages. The pointed ejection plunger was required to hit the center of the delay fuze in order to insure reliable ignition and thus accurate positioning of the ignition device was necessary. Also the pyrotechnic delay elements and the black powder was very susceptible to moisture intrusion which caused excessive delay times and duds.

SUMMARY OF THE INVENTION A cylindrical case is provided and has a center bore therethrough. A primer closes the aft end of the case and a nozzle closes the forward end of the case. The

nozzle is provided with an orifice whose length is partly a pyrotechnic fuze.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an end view of a preferred embodiment of the present invention; and

FIG. 2 is a sectional view taken on line 2--2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, there is shown a case 11 having a central bore 12 therethrough, and a primer l3 closes the aft end of case 11. A nozzle 14 is attached to the forward end of case 11 by crimping. As best shown in FIG. 2 of the drawing, nozzle 14 is provided with an orifice 15 that has a flared portion 16 and an ignition pellet 17 is contained in bore 12 adjacent nozzle 14. A frangible disk 18 is attached, as by cementing, to the front face of nozzle 14 thereby closing bore 12 to prevent any moisture from entering and affecting ignition pellet 17. By way of example, case 11 might be aluminum, nozzle 14 might be brass and disk 18 might be plastic, such as polyester film. Ignition pellet 17 might be comprised of powdered magnesium and tef- Ion.

OPERATION In operation, a firing pin detonates primer l3 and the pressure and flame from primer 13 ruptures frangible disk 18. The flame from primer 13 also ignites ignition pellet 17, and the hot gases and flame generated by the burning of ignition pellet 17 are directed outwardly through orifice 15 of nozzle 14 and are used to ignite a pyrotechnic delay element.

We claim:

1. An ignition device for a pyrotechnic fuze comprising,

a case having a central bore therethrough,

a primer closing one end of said central bore,

a nozzle crimped to the other end and closing said central bore, said nozzle having a circular orifice in the forward end thereof and an outwardly extending flared portion in the aft end thereof,

an ignition pellet positioned in said central bore adjacent said flared portion of said nozzle, and

a frangible disk attached to the outer end of said nozzle and closing said circular orifice of said nozzle. 

1. An ignition device for a pyrotechnic fuze comprising, a case having a central bore therethrough, a primer closing one end of said central bore, a nozzle crimped to the other end and closing said central bore, said nozzle having a circular orifice in the forward end thereof and an outwardly extending flared portion in the aft end thereof, an ignition pellet positioned in said central bore adjacent said flared portion of said nozzle, and a frangible disk attached to the outer end of said nozzle and closing said circular orifice of said nozzle. 